Apparatus and method for grading articles

ABSTRACT

An apparatus and method for inspecting and sorting articles such as fruit and vegetables in which the articles are presented, on a conveyor, under a viewing device and classified. A take-off position is determined from the classification and the article is removed by means of an independently actuated ejector mechanism.

TECHNICAL FIELD

This invention relates to a method of and apparatus for automaticallysorting articles and more particularly to a method and apparatus forautomatically sorting articles such as harvested fruit and vegetablecrops in accordance with their shape, size and the presence andseriousness of defects.

It has been conventional practice when sorting such articles toestablish the grades required and the criteria for each grade in advanceof the sorting operation and then for workers to manually randomly sortproduce in accordance with the pre-determined grades. The disadvantageof such a system is that it is necessarily labour intensive andaccordingly costly.

An object of the present invention is to provide improvements inrelation to one or more matters discussed herein and/or generally.

According to the invention there is provided apparatus for gradingarticles such as fruit and vegetables, and a method of grading articlessuch as fruit and vegetables as defined in the accompanying claims.

SUMMARY OF THE INVENTION

In an embodiment of the invention apparatus for inspecting and sortingarticles such as fruit and vegetables comprises a spool or rollerconveyor onto which articles are presented from a discharge chute. Thedischarge chute may oscillate to assist alignment and movement of thearticles discharged onto the conveyor. The conveyor carries the objectsunder a viewing device or inspection zone at which a camera-typescanning unit is mounted overhead of the conveyor in such a way that thecamera can scan the articles as they pass underneath. The rollerelements of the conveyor are driven to rotate during the scanningprocess in order that the articles thereon also rotate to afford as fulla view as possible of the articles.

Apparatus such as a video grabber converts the visual image dataprovided by the camera. This information is passed to a centralprocessing unit which analyses and evaluates the images of theindividual article created by the camera as to size(length/diameter/volume), grade (rot, cracks, damage etc) andorientation as well as position in the direction of travel and the spaceoccupied on the conveyor as the article sits in the valleys formedbetween successive roller elements. Any defects present arecharacterised into groups in accordance with pre-determinedcharacteristics and converted into a numerical value, such as apercentage. An operator establishes, by means of a set-up screen, therequired characteristics or numerical value of the particular grade tobe selected for. The operator controlled program then establishes adischarge position where selected articles will be removed from theconveyor according to the required classification, that is by size,grade or direction of orientation. The central processing unit woulddetermine the point at which the selected article is to be removed andhow many actuators to activate to cause article removal devices or fliplevers located just under the full length of the product to flip thearticle onto the take out conveyor or flume.

Tracking means mazy ho provided on the conveyor so as to enable theposition of each article to be followed, thus facilitating removal ofthe particular article from the conveyor on reaching the requireddischarge position.

Articles may be removed or ejected from the conveyor at the requiredposition by article removal devices. A plurality of devices may beprovided and mounted at intervals between the roller elements and acrossthe width of the conveyor. The devices comprise a flip lever.

In another embodiment of the invention said article removal elements maybe in the form of projections. Said projections may be of finger-likeform. The finger-like projections may be inclined forwardly with respectto their direction of angular movement when actuated.

In a further embodiment of the invention the flip levers may be shaped,for example, diablo shaped, to suit the particular type of articlesbeing graded such as citrus fruits.

The flip lever may be pivotally mounted beneath the conveyor. Each fliplever, when activated, moves in an upward direction and passes betweentwo successive pairs of roller elements to contact an article lying onthe conveyor. The upward momentum imparted to the article as a result ofcontact between the flip lever combined with the forward momentum fromthe roller conveyor causes the article to be carried upwardly, or“flipped” onto a discharge belt or flume while the flip lever retracts.

Transverse overhead take-out conveyors or water flumes are provided tocollect and deliver to the side of the machine those articles which areremoved from the conveyor when the required position is reached. Thearticles are flipped up and into the take-out conveyor or flume by theflip levers in the roller conveyor system.

In an embodiment two or more article removal devices such as flip leversmay be provided for each article to be removed, wherein the size of thearticle may determine the number and/or sequence of elements which areactuated at any one time.

Those articles remaining on the conveyor will be discharged over the endof said conveyor. In most cases these articles will represent the primegrade required.

Any number of discharge belts and corresponding ejector mechanisms maybe provided depending on the number of classifications required during agiven. operation.

A typical machine will have three take-out positions with the requiredejector mechanisms and discharge belts in addition to the over the endseparation point making a total of four although any number of take-outpoints may be provided, It is envisaged that the take-out points will beof modular construction and the length of the machine may be extended byadding further such points. It is also envisaged that the apparatusherein before described will replace the conventional inspectionconveyor normally positioned between the station for washing/sorting ofarticles and packing which is generally manned by a number of people.

According to the invention there is also provided a method forinspecting and sorting articles such as fruit and vegetables, saidmethod comprising the step of locating the articles on a conveyor forexample by discharging the articles from a chute onto a spool or rollerconveyor. The chute may be caused to oscillate to assist alignment ofthe articles. The articles on the conveyor pass under a viewing deviceor inspection zone at which the articles are inspected and scanned asthey pass. The method comprises the step of analysing an image or otherdata from each article by a data processing and control system, saiddata being processed in order to classify the articles according toshape and/or size and/or defects. The method comprises the step ofcausing a selection of said classified articles to be removed or ejectedfrom the conveyor in response to said classification. During the step ofremoval or ejection, the article is caused to be lifted from the surfaceof the conveyor and moved to a discharge conveyor.

An advantage of the invention described herein is that it provides afaster, less labour intensive and accordingly a more economical methodfor sorting articles such as fruit and vegetables.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way ofexample with reference to the accompanying drawings in which:

FIG. 1 shows a side elevation view of the inspecting and sortingapparatus according to the invention;

FIG. 2 shows a sectional view taken along the line A—A of the apparatusof FIG. 1;

FIG. 3 shows a side elevation view of a section of a roller assemblyaccording to the invention;

FIG. 4 shows a side elevation view of a flip lever;

FIG. 5 shows a side elevation view of a roller element;

FIG. 6 shows a side elevation view of a roller element, flip lever andassociated actuating means;

FIG. 7 shows a side elevation view of three flip levers and associatedroller elements, showing the position of the flip levers in relation toone another and the movement of a flip lever;

FIG. 8 shows a side elevation view, schematic in character of a portionof the apparatus according to the invention showing the position of anarticle to be sorted in relation to the roller elements and flip levers;and

FIGS. 9a-9 d show a side view, schematic in character of the action ofan alternative flip lever.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in the drawings, apparatus for conveying and inspectingarticles 10 comprises a spool or roller conveyor 12. Said rollerconveyor 12 comprises a series of roller assemblies 14. Each rollerassembly 14 is formed by mounting a plurality of roller elements on ahexagonal steel shaft 16 having bushings 18 at each end and a sprocket20 attached near one end. The roller elements 22 comprise disc shapedrollers with a central aperture 24 which is hexagonal to enable them tobe received on the shaft 16, and a round hub portion 26 on one side.

The aperture 24 could be of any other suitable shape such as triangular,pentagonal, or square but in practice a roller element 22 with ahexagonal-shaped aperture mounted on a correspondingly shaped shaftprovides the best drive. Also mounted on the shaft 16 and between theroller elements 20 is a flip lever 28. Said flip lever 28 comprises around portion 30 having an aperture 32 which is round for receiving thehub 26 of the roller element 20, a substantially horizontally extendingarm or lever portion 34 and a substantially vertically extending legportion 36, all of which may be moulded as a single body 38 to providethe flip lever 28 with additional strength.

The aperture 32 may be formed off-centre with respect to the bodyportion 38 of the flip lever 28. The arm portion 34 of the flip lever 28extends in a direction opposite to that of the flow of items on theconveyor 12 (ie upstream) and extends towards and rests in the region ofthe top of the pivot point of the following flip lever 28 located on thenext shaft 16. The body portion 38 is shaped in the region of contact 44to accommodate the round portion 30 of the following flip lever 28. Theleg portion 36 extends in a downwardly direction below the conveyor 12.

The flip lever 28 is constructed such that the arm portion 34 is belowthe upper edge of the roller elements 22, such that the upper face ofthe arm portion 34 is positioned just below the articles (such asfruit/vegetables to be graded) as these lie in valleys 46 formed by andbetween the rollers elements 22 of successive roller assemblies 14.Smaller size or diameter articles may lie directly on top of the upperface of the arm portion 34. The leg portion 36 of the flip lever 28extends in a downward direction past the bottom of the roller elements22. By extending downwardly below the conveyor 12, the leg portion 36may be actuated by suitable actuating means 48 positioned beneath theflip lever 28. The leg portion 36 is also formed with an stop or lugportion 42.

The roller assemblies 14 are attached at their end points to drivechains 50 which pass over the sprockets 20 located at the end of theconveyor 12. An electric motor drives the sprockets 20 at the dischargeend of the conveyor 12. As the motor drives the sprockets 20, the chains50 on each side of the roller conveyor 12 advance, along with all of theroller assemblies 14 which are carried perpendicularly between thechains 50.

By alternately installing a roller element 22 then a flip lever 28 onthe shaft 16, a flip lever/roller assembly 14 may be created of anyaxial length. A shaft collar will be used on each end of the shaft tohold the assembly together. The length of the hub 26 and diameter of theroller element 22 is such that the flip lever 28 is free to rotate onthe hub 26.

The bushings 18 at the ends of the shafts 16 are used to connect pins onstandard pin chain which is used to form the conveyor 12. In thismanner, the shaft 16 assembly is free to rotate on the chain pins. Theendless chains on each end of the shaft 16 are carried by a plasticchain support guide as they advance.

The sprockets 20 mounted on the end of each shaft 16 may be driven by aspin chain system 50 a driven independently to the main chain 50. Thespin chain moves over a solid support guide 64 which raises the chain 50a to engage with the sprockets 20. This causes rotation of the sprockets20 and the roller elements 22 up the in-feed section and under thecamera 58, and the entire roller assembly 14 may be rotated at whateverspeed is desired. The flip levers 28, being free on the hubs 26 of theroller elements 22, are not rotated by the drive to the shaft 16. Theroller elements 20 stop rotating after the last view when the guide 64is lowered at position 66 to disengage the chain 50 a before the chainsrun onto the sprocket 20 a.

Actuating means for the flip levers 28 are positioned beneath the rollerconveyor 12, transverse to the direction of flow, with one rank or arrayof actuators for each take-off position desired. The actuators wouldcomprise pneumatic, solenoid or other suitable devices that move anactuating cylinder, block or ramp 52 into a position in the path of theleg portion 36 of the respective flip lever 28. Said cylinder 52 isformed with a flange or boot portion 54.

Actuation of the cylinder 52 causes it to move in an upwardly directiontowards the conveyor 12. Upward movement of the cylinder 52 results inthe flange or boot portion 54 extending past the downwardly extendingleg portion 34 of the flip lever 28, such that the two come into directcontact, with the cylinder 52 and flange or boot 54 acting as a triplever. The flange or boot 54 contacts a correspondingly shaped lip orflange 40 on the leg portion 34 of the flip lever 28. On contact, theflip lever 28 is temporarily prevented from advancing forwardly, but thecontinued forward movement of the roller assembly 14 on which the fliplever is mounted, causes the flip lever 28 to turn on the hub 26 of thecorresponding roller element 22, slowly at first and then withincreasing angular acceleration as the forward movement of the rollerassembly 14 continues.

The angular movement of the flip lever 28 causes the arm portion 34thereof to rotate forwardly and contacts an article located on theconveyor 12. Such contact causes the article to be lifted or “flipped”away from the conveyor 12. This lifting action, together with theforward speed of the conveyor, results in an article being liftedupwardly and forwardly from the conveyor 12 onto an appropriate crossconveyor or flume 62. Angular movement of the flip lever 28 continuesuntil the stop portion 42 contacts a roller element 22 located on thefollowing roller assembly 14. The contact between the stop means 42 andthe roller element 14 halts the angular movement of the flip lever andsaid flip lever retracts to its non-actuated position. The body portion38 of said flip lever 28 is shaped in the region 45 to prevent the fliplever 28 fouling the corresponding roller element when said flip lever28 is actuated.

In use, the typical operation of the invention is described below. Ain-feed delivery unit feeds the articles to be graded and sorted evenlyacross the width of the roller conveyor 12. Such devices will deliverthe articles from conveyors or elevators and cause them to be evenlyspread and properly positioned for effective filling of the valleys 46on the roller conveyor 12.

The articles are delivered in a continuous flow to the delivery unitwhere they are positioned so that as the roller conveyor 12 advancesunderneath, the products can drop into the valleys 46 formed betweeneach roller assembly and will fill the valleys 46 formed between theroller assemblies 14 across the width of the conveyor 12.

Excessive volume of articles would cause “doubles” to occur so it isimportant the feed rate is such that excessive “doubling” (two articlesin one valley 46, or overlapping) does not occur. The roller assemblies14 are driven by their sprockets 20 at any speed of forward or reverserotation (with respect to the conveyor's travel direction) to assist infilling the valleys 46, ensuring singulation and preventing doubles.

As the articles are delivered on to the roller conveyor 12, the rollerassemblies 14 are advancing, usually but not exclusively, up an inclinesufficient to help align the products in the valleys 46 formed betweenthe rollers. The roller assemblies 14 advance at a constant rate, beingpulled by the chains on either end of the roller assemblies 14. Theroller elements 22 are rotated by the sprockets 20 at either end of theshafts 16 which are being turned by a separate moving chain system.

The articles on the conveyor are also being rotated by the rollerelements 22 as they pass underneath the camera viewing area 56 such thatthe articles rotate by at least one full revolution. The cameras 58 willtake one or more views of the articles in order to obtain as full a viewas possible of all sides of the articles. The required take-off positionis determined from the position on the conveyor occupied by article whenthe final view of the article was taken. Accordingly, once the conveyor12 passes under the viewing section 56, the roller elements 22 are nolonger driven to rotate. This is because when the roller elements 22 arerotating, the articles carried thereupon drift across the valleys 46 andthe relative position of the article on the conveyor 12 is not stable.As the take-off position of the article is calculated from the last viewof the article taken, in order to be removed at the correct position thearticle must not have moved from that particular point on the conveyor12. Articles not ejected from the conveyor 12 are carried by the rollerelements 22 through the take-off section 60.

At a first take-off position, articles of a certain size, grade ororientation are flipped up and forward into a cross flow take-offconveyor or flume 62. At a further take-off point, articles of adifferent size, grade or orientation are flipped up and forward into afurther cross flow take-off belt or flume located at this position. Longarticles such as carrots where orientation is important for subsequentprocessing or packing, may be selectively removed at different take offpoints depending on the direction the carrot is facing (orientation).When flipped up into the cross flow take-off conveyance, the carrotremains pointing the same direction as it lay in the valley 46 formedbetween the roller elements 22, because a plurality of flip levers 28are actuated at the same time across its length to propel the carrotwithout reorientating.

The combination of a simple carrier system, sophisticated camera andprocessing system and simple forward flip lever system for removal ofthe products into overhead cross conveyances results in an economic wayto size, grade and orient a wide variety of fruit and vegetablecommodities.

What is claimed is:
 1. A method of grading articles including fruits andvegetables, comprising the steps of: a) conveying the articles to begraded: b) monitoring the articles as they are conveyed; c) acting toremove at least one grade of article in response to data provided duringthe monitoring step; and d) removing articles by selectively actuatingan array of article removal devices located below said articles, saidarticle removal devices being actuated by signals generated during themonitoring step; characterised by the step of: e) causing the articleremoving devices to contact the articles to be removed, said contactimparting upward momentum to the articles, the upward momentum causingthe articles to be propelled or flipped upwards away from the surface ofthe conveyor, in a direction substantially parallel with the directionof the conveying of the articles, towards a discharge location.
 2. Amethod of guiding articles according to claim 1 characterised in thatsaid array of said article removal devices are conveyed with thearticles and actuated by an array of actuators controlled by signalsgenerated during monitoring of the articles.
 3. A method of gradingarticles according to claim 2 characterised in that said array ofarticle removal devices being disposed in rows across the conveyingwidth of said article.
 4. A method of grading articles according toclaim 1 characterised by conveying said articles on a belt-type conveyorcomprising successive rows of said article removal devices interspersedwith rows of drivable, rotatable article turning elements and drivingsaid article turning elements to align said articles with rows for saidmonitoring step.
 5. A method of grading articles according to claim 1characterised by interrupting the drive to said device turning elementsbetween said monitoring step and said step of actuating said articleremoval devices.
 6. A method of grading according to claim 1characterised by the articles being turned prior to monitoring wherebythe articles on the conveyor can be presented in the preferred positionfor monitoring.
 7. A method of grading according to claim 6characterised by the step of suspending the turning of the articlesafter the monitoring step whereby migration of the article is prevented.8. A method of grading articles including fruit and vegetables,comprising the steps of: locating the articles on a spool or rollerconveyor element; causing the articles on the conveyor to pass under aninspection device at which the articles are inspected and scanned asthey pass to produce inspection data; analyzing the inspection data fromsaid articles by a data processing system, said data being processed andclassified according to a predetermined criteria; and causing aselection of said articles to be removed from the conveyor in responseto said classification, wherein during the step of removal, the articleis caused to be propelled upwards from the surface of the conveyor, in adirection substantially parallel with the direction of the conveying ofthe articles, towards a discharge device.
 9. Apparatus for inspectingand sorting articles including fruit and vegetables, comprising: a) atleast one drivable spool or roller conveyor means onto which articlesare presented; b) an inspection device under which the articles areconveyed which inspects and scans the articles as they pass; c) acontrol system for analysing and processing the data obtained andadapted to classify the articles according to shape and/or size and/ordefects present; d) an array of article removal devices located belowsaid articles which may be actuated to displace/remove articles from theroller conveyor means in response to such classification; and e) atleast one discharge location at which articles displaced/removed fromthe roller conveyor are received; characterised in that: f) theactuation of said article removal device causes contact with thearticles to be removed, thereby imparting upward momentum thereto, saidupward momentum causing the article to be propelled or flipped upwardsaway from the surface of the roller conveyor, in a directionsubstantially parallel to the direction of the conveying of thearticles, towards a discharge location.
 10. Apparatus for gradingarticles according to claim 9 characterised in that said article removaldevices are located on the conveyor and are actuated by an array ofactuators controlled by signals generated when the articles are viewedor inspected.
 11. Apparatus for grading articles according to claim 10characterised by said article removal devices being disposed in rowsacross the conveying width of said article.
 12. Apparatus for gradingarticles according to claim 9 characterised in that said conveyorcomprises a belt-type conveyor on which are provided successive rows ofsaid article removal devices interspersed with rows of drivable,rotatable turning elements, said article-turning elements acting to turnsaid articles to align them within said rows to facilitate inspection.13. A apparatus for grading articles according to claim 12 characterisedin that said article turning elements act to turn said articles as theypass the inspection device whereby a full view of the article isobtained.
 14. Apparatus for grading articles according to claim 12characterised in that drive means to said article turning elements issuspended after the articles have passed the inspection device wherebysaid articles cease to turn thus preventing migration.
 15. Apparatus forgrading articles according to claim 9, characterized in that at leasttwo conveyors are provided, the second conveyor, which receives articlesejected from the first conveyor, is located above the first conveyorwhich presents the articles to be graded.
 16. Apparatus for gradingarticles according to claim 15 characterised in that said secondconveyor comprises a water flume.
 17. Apparatus for grading articlesincluding fruit and vegetables, comprising: a) apparatus having at leastone drivable spool or roller conveyor means onto which articles arepresented; b) a viewing or inspection device under which the articlesare conveyed which inspects and scans the articles as they pass; c) acontrol system for analyzing and processing the data obtained andadapted to classify articles according to shape and/or size and/ordefects present; and d) a mechanism for displacing/removing articlesfrom the roller conveyor means in response to said classification, andat least one discharge location at which articles displaced/removed fromthe roller conveyor are received; characterized in that: e) theactuation of said article removal devices causes the articles to bepropelled upwardly from the surface of the roller conveyor, in adirection substantially parallel to the direction of the conveyingarticles, towards a discharge location.
 18. Apparatus according to claim17 characterised in that the mechanism for sorting comprises an array ofarticle removing devices mounted on said roller conveyor means. 19.Apparatus according to claim 18 characterised in that said articleremoving devices comprise flip levers or projections.
 20. Apparatusaccording to claim 19 characterised in that said flip lever comprises around portion with an aperture, a substantially horizontally extendingarm portion, and a substantially vertically extending leg portion. 21.Apparatus according to claim 20 characterised in that said flip levercomprises a round portion with an aperture, a substantially horizontallyextending arm portion, a substantially vertically extending leg portion,all being moulded as a single body.
 22. Apparatus according to claim 20characterised in that said arm portion extends in a direction oppositeto that of the flow of articles on the conveyor.
 23. Apparatus accordingto claim 19 characterised in that said projections or flip levers aremounted at intervals along the length of the roller conveyor means. 24.Apparatus according to claim 23 characterised in that said projectionsor flip levers are actuable independently of the roller elements of saidroller conveyor.
 25. Apparatus according to claim 24 characterised inthat the arm portion of said projections or flip levers are caused tomove in a generally upwardly direction in relation to the conveyor. 26.Apparatus according to claim 25 characterised in that on actuation thearm portion of said projections or flip levers are caused to move in agenerally upwardly direction between successive rollers of the convertorso as to contact the article to be removed from the conveyor. 27.Apparatus according to claim 22 characterised in that said flip leversor projections are caused to move by an actuating cylinder locatedbeneath the conveyor.
 28. Apparatus according to claim 27 characterisedin that said actuating cylinder is formed with a boot.
 29. Apparatusaccording to claim 28 characterised in that said actuating cylinder andboot move into the path of the leg portion of the flip lever acting as atrip therefor.
 30. Apparatus according to claim 25 characterised by saidprojections or flip levers being of finger-like form.
 31. Apparatusaccording to claim 29 characterised by said projections or flip leversbeing inclined forwardly with respect to their own direction ofrotation.
 32. Apparatus according to claim 17 characterised in that theinspection device comprises a camera scanning unit.
 33. Apparatusaccording to claim 32 characterised in that said camera scanning unit ismounted overhead above the conveyor so as to enable the articles to beviewed as they pass beneath.
 34. Apparatus according to claim 33characterised in that said camera scanning unit is linked to the controlsystem which includes a central processing unit wherein data obtainedfrom analysing the image of each article scanned is collated, thearticle classified according to the required criteria and a dischargeposition established for each article according to the classification.35. Apparatus according to claim 34 characterised in that tracking meansis provided on the conveyor so as to enable the position of each articleto be followed thus facilitating removal of the particular article fromthe conveyor on reaching the required position.
 36. Apparatus accordingto claim 17 characterised in that said discharge conveyor comprises atransverse overhead take-out conveyor to collect and deliver articlesplaced therein.
 37. Apparatus according to claim 17 characterised inthat said discharge conveyor comprises a water flume to collect anddeliver articles placed therein.